Recent genome-wide association studies (GWAS) have reported multiple risk loci associated with risk of colorectal cancer (CRC), some of which are involved in the transforming growth factor beta (TGFβ) signaling pathway. We systematically examined associations of common genetic variations in the TGFβ signaling pathway and environmental factors with CRC risk using a two-staged case-control study in a Chinese population. A set of 77 single-nucleotide polymorphisms (SNPs) in 10 candidate genes involved in the TGFβ signaling pathway and several environmental factors including sex, age, smoking and drinking were examined by random forest (RF) to capture the potential gene-gene and gene-environment interactions in stage 1 of the study with 443 CRC patients and 480 controls. Three promising SNPs (SMAD7 rs11874392, TGFBR1 rs10988706 and rs6478972) selected by the RF method were genotyped in stage 2 comprising 351 cases and 360 controls for validation. SMAD7 rs11874392 presented consistently significant associations with a risk of CRC at both stages, with odds ratio = 1.41 (95% confidence interval = 1.21-1.63) using additive modes in combined analyses. Moreover, the potential interactions between SMAD7 rs11874392, TGFBR1 rs10988706 and rs6478972 were indicated consistently in both stages of the study by using pair-wise interaction and multilocus genotype pattern analysis. Additionally, gene-smoking interactions for rs11874392, rs10988706 and rs6478972 were also found to enhance the risk of CRC at both stages, with P for multiplicative interaction equal to 1.162×10(-6), 8.574×10(-8) and 9.410×10(-8) in combined analyses, respectively. This study emphasized the substantial role of the TGFβ signaling pathway in CRC, especially in interaction with smoking.

BackgroundMetabolic syndrome traits play an important role in the development of colorectal cancer. Adipokines, key metabolic syndrome cellular mediators, when abnormal, may induce carcinogenesis.Methodology/Principal FindingsTo investigate whether polymorphisms of important adipokines, adiponectin (ADIPOQ) and its receptors, either alone or in combination with environmental factors, are implicated in colorectal cancer, a two-stage case-control study was conducted. In the first stage, we evaluated 24 tag single nucleotide polymorphisms (tag SNPs) across ADIPOQ ligand and two ADIPOQ receptors (ADIPOR1 and ADIPOR2) among 470 cases and 458 controls. One SNP with promising association was then analyzed in stage 2 among 314 cases and 355 controls. In our study, ADIPOQ rs1063538 was consistently associated with increased colorectal cancer risk, with an odds ratio (OR) of 1.94 (95%CI: 1.48–2.54) for CC genotype compared with TT genotype. In two-factor gene-environment interaction analyses, rs1063538 presented significant interactions with smoking status, family history of cancer and alcohol use, with ORs of 4.52 (95%CI: 2.78–7.34), 3.18 (95%CI: 1.73–5.82) and 1.97 (95%CI: 1.27–3.04) for smokers, individuals with family history of cancer or drinkers with CC genotype compared with non-smokers, individuals without family history of cancer or non-drinkers with TT genotype, respectively. Multifactor gene-environment interactions analysis revealed significant interactions between ADIPOQ rs1063538, ADIPOR1 rs1539355, smoking status and BMI. Individuals carrying one, two and at least three risk factors presented 1.18–fold (95%CI:0.89–fold to 1.58–fold), 1.87–fold (95%CI: 1.38–fold to2.54–fold) and 4.39–fold (95%CI: 2.75–fold to 7.01–fold) increased colorectal cancer risk compared with those who without risk factor, respectively (P trend <0.0001).Conclusions/SignificanceOur results suggest that variants in ADIPOQ may contribute to increased colorectal cancer risk in Chinese and this contribution may be modified by environmental factors, such as smoking status, family history of cancer and BMI.

Single genetic variation may only have a modest effect on risk of gastric cardia adenocarcinoma (GCA) because this malignancy is believed to result from complex interactions among multiple genetic and environmental factors. However, it has been a challenge to characterize multiple interactions using parametric analytic approaches. This study utilized a multi-analytic strategy combining logistic regression (LR), multifactor dimensionality reduction (MDR) and classification and regression tree (CART) approaches to explore high-order interactions among smoking and 12 polymorphisms involved in different processes of carcinogenesis in 344 GCA patients and 324 controls. LR, MDR and CART analyses consistently suggested MMP-2 C-1306T polymorphism as the strongest individual factor for GCA risk. Intriguingly, a high-order interaction was consistently identified by MDR, LR and CART analyses. In MDR analysis, the three-factor model including MMP-2 C-1306T, FASL T-844C and FAS G-1377A yielded the highest testing accuracy of 0.632. When analysing combined effect of these three polymorphisms by LR, a significant gene dose effect was observed with the odds ratios (ORs) being increased with increasing numbers of risk genotypes (P(trend) = 4.736 × 10⁻¹²). In CART analysis, individuals carrying the combined genotypes of MMP-2 -1306CC, FASL-844TT or TC and FAS -1377AA had the highest risk for GCA (OR = 4.58; 95% confidence interval, 2.07-10.14) compared with the lowest risk carriers of the MMP-2 -1306CT or TT genotype. These results suggest that MMP-2 C-1306T polymorphism is an important risk factor for GCA and the multifactor interactions among polymorphisms in MMP-2, FASL and FAS play more important role in the development of GCA.

These findings suggest that genetic polymorphisms in the P53 pathway may be promising biomarkers for individualized chemotherapy and prognosis of NSCLC patients.

BackgroundA common genetic variant, rs4939827, located in SMAD7, was identified by two recent genome-wide association (GWA) studies to be strongly associated with the risk of colorectal cancer (CRC). However, the following replication studies yielded conflicting results.Method and FindingsWe conducted a case-control study of 641 cases and 1037 controls in a Chinese population and then performed a meta-analysis, integrating our and published data of 34313 cases and 33251 controls, to clarify the relationship between rs4939827 and CRC risk. In our case-control study, the dominant model was significant associated with increased CRC risk [Odds Ratio (OR) = 1.46; 95% confidence interval (95% CI), 1.19–1.80]. The following meta-analysis further confirmed this significant association for all genetic models but with significant between-study heterogeneity (all P for heterogeneity <0.1). By stratified analysis, we revealed that ethnicity, sample size, and tumor sites might constitute the source of heterogeneity. The cumulative analysis suggested that evident tendency to significant association was seen with adding study samples over time; whilst, sensitive analysis showed results before and after removal of each study were similar, indicating the highly stability of the current results.ConclusionResults from our case-control study and the meta-analysis collectively confirmed the significant association of the variant rs4939827 with increased risk of colorectal cancer. Nevertheless, fine-mapping of the susceptibility loci defined by rs4939287 should be imposed to reveal causal variant.